resolveDeleteSync gated mirror teardown on the per-video opt-in flag,
which lives only in this browser's localStorage. A video shared on one
device and deleted from another (or after a cache clear) skipped teardown,
orphaning the NIP-71 mirror on other apps. Delete now always attempts
teardown when the feature is on (remove() is idempotent). The flag still
gates the UI toggle and publishing.
Co-Authored-By: Claude Opus 4.8 <[email protected]>